Oncologic results of conventional laparoscopic TME: is the intramesorectal plane really acceptable?

Excerpt

After two decades of conventional laparoscopic surgery for rectal cancer, during which a plethora of promising results were reported and expected, the simultaneous publication of the two most recent multicenter randomized controlled trials (RCT) in JAMA (i.e. ACOSOG Z6051 and ALaCaRT trials) started a debate regarding its oncological safety [1, 2]. These studies presented some similarities, such as a shared main outcome defined by the achievement of a composite pathologic endpoint including free margins (radial and distal − 1 mm) and appropriateness of mesorectal excision (i.e. obtaining an intact mesorectum with defects no deeper than 5 mm) [1, 2]. Remarkably, the oncologic non-inferiority for laparoscopy compared with open surgery was not established [1, 2]. As they were not identical studies, it is crucial to mention that method of grading the mesorectal quality adopted in each was apparently different (Table 1). ALaCaRT trial used the Dutch Colorectal Cancer Group (DCCG) classification, as the vast majority of contemporary literature, and complete resections (with mesorectal defects up to 5-mm) were considered successful and were included alone in the composite main outcome. However, researchers from the ACOSOG Z6051 trial selected a different grading system. They considered complete specimens those with a smooth surface of mesorectal fascia with all fat contained in the enveloping and nearly complete specimens those with a mesorectal envelope that was intact except for defects of no more than 5 mm. Interestingly, only their complete resections (no defects in the mesorectum) were initially considered appropriate. However, after a modification in the protocol during the study their own definition of nearly complete specimens (defects up to 5 mm) was also considered adequate [1]. Therefore, their endpoint became the same as complete resections as defined by DCCG and in the ALaCaRT trial. …